I shared a video about the ontological argument that gives the absolute bare-bones of the argument on my Facebook recently. A friend came along and raised a point that that friend said had bothered them for a while. The objection was that could not such an argument be used to argue for the existence of an evil god just as much as for a good God? I typed up a response I would like to also share here.
The first thing I’d point out is that such an objection to the argument assumes that evil is itself ontologically extant rather than a deprivation. That is, it assumes evil is itself a thing, rather than being that which is not-good. Although that is not an implausible position, it would take establishment of evil as a real existing thing in order for the argument to work.
Another difficulty is that it seems intuitively false that maximal greatness could include “maximal evil.” That’s a reason things like the maximally great pizza don’t really work as objections to the argument–maximally great pizzas are not only nonsensical (for greatness of pizza depends upon one’s taste) but they also have nothing intrinsic in them to entail maximal greatness. Such an objection would have to establish not only that evil exist on its own rather than as a deprivation, but also that evil is a kind of “great-making property.” Since it seems clear that evil is not a “great-making property,” the burden of proof is on any who wishes to demonstrate that it is.
A third problem is that the argument must see maximally good and maximally evil as epistemically on par with each other. For the argument to work, evil and good have to be effectively even when it comes to probability. But that is a very complex argument to make.
Finally, if all of these difficulties were overcome, the one making the argument has effectively made an argument for radical skepticism, to the point that we could not really be epistemically sure of anything. I’ve argued for this last point at length. Basically, the point is that if it is true that if A and B are epistemically on par with each other, we have no way of distinguishing between A and B, then it follows that we cannot be sure of anything or making distinctions in everyday life. For it is the case that we can construct for ANY scenario X a scenario Y that is epistemically on par with it (at least in principle) such that Y _may_ be the case instead. And if that’s true, and the point made by the notion of an evil God is true, then we must adhere to radical skepticism. In other words, a reductio ad abusdum defeats the argument.